Photoacoustic tomography (PAT) is an imaging technology that uses light, in which an acoustic wave produced by irradiating a subject being examined or imaged with pulsed laser light to thermally expand an object being measured in the subject is received and is converted into an image. PAT allows imaging of the in-vivo distribution of hemoglobin, glucose, or the like of which the absorption band lies in the wavelength of the pulsed laser light to be radiated. PTL 1 describes a method for creating a three-dimensional image of a large examination region using PAT, in which acoustic waves are received at a plurality of positions by a mechanically moving acoustic wave receiver while being sequentially positioned.
One of effective imaging methods for the internal structures of a relatively large subject being examined or imaged, such as a breast, using PAT is to, as disclosed in PTL 1, mechanically scan the surface of the subject with an acoustic wave receiver composed of electroacoustic transducers arranged in a one-dimensional or two-dimensional array. It is desirable that the time required for such mechanical scanning be as short as possible in terms of reduced load on the examinee.